Messages in this thread |  | | From | (Alan Cox) | Subject | Re: Would Linux still be Linux if it didn't have an MMU was Re: Linux Port to NS486? (without MMU) | Date | Thu, 17 Oct 1996 22:40:49 +0100 (BST) |
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> When I read the man page for mmap it states that > "Linux 0.99.11 can't map files etc., and can't do > other things documented here" -- I probably have > old manpages. This leads me to think that early > linux didn't have much support for mmap.
Page mapping is used as the basis for the whole VM and much of the I/O subsystem. Its used for shared libraries, for system5 shared memory and for mmap.
To build a kernel without it is possible, you'd need to go back to the old disk I/O system, drop the shared libraries (initially anyway - its in theory possible to build the shared libraries specially to use a different segment - not nice though).
You can keep all the protection and stuff as the segmented architecture still has permissions. You'd end up with a Linux kernel that needed the VM stuff rewriting, the paging changed to swapping, and the old style disk I/O code using. Doable but not trivial
Alan
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